Matrices and sealants which are based on sulfur-containing polymers and which comprise a photoinitiator, curing and coating methods, and use of said matrices and sealants

Patent metadata

Field	Value
Publication number	US-11124674-B2
Application number	US-201916445942-A
Country	US
Kind code	B2
Filing date	Jun 19, 2019
Priority date	Apr 12, 2012
Publication date	Sep 21, 2021
Grant date	Sep 21, 2021

Abstract

A method for curing a mixture of a matrix and a curing agent based on sulfur-containing polymers on command and so rapidly that a tack-free surface results. A method for coating a substrate with the composition and of curing a sealant is also provided. The matrix and curing agent containing sulfur-containing polymers. The mixture is an uncured mixture with an isocyanate content, and the matrix is uncured and contains a mercaptan-terminated base polymer based on at least one polyether, polythioether, polysulfide or copolymers thereof. The uncured matrix, the curing agent, or both contain at least one photoinitiator based on sterically-inhibited tertiary amines. The mixture cures in the temperature range of −10 to +70° C. after the high-energy actinic radiation is applied. Corresponding matrices A, mixtures B, curing agents, sealant systems, and substrates, e.g., aircraft are contemplated.

First claim

The invention claimed is:

1. A sealant formed from a mixture B comprising
an uncured matrix A based on sulfur-containing polymers, wherein the sulfur-containing polymers are mercapto-terminated base polymers based on polyether, polythioether, polysulfide, copolymers thereof, and/or mixtures thereof, wherein the mercapto-terminated polymer has a mercaptan content, based on the reactive SH groups to the total weight of the polymer, in the range of 0.8 to 8 wt %; and
a curing agent containing isocyanate, the isocyanate having an average functionality in the range of 1.5 to 3.2;
wherein the uncured matrix A, the curing agent or both contain a photoinitiator, which includes an α-aminoketone, which is activated by exposure to high-energy actinic radiation and releases an amine radical;
wherein the sealant is free of (meth)acrylate-based compounds/polymers; and
wherein the sealant is formed when curing of mixture B starts.

2. An uncured matrix A based on sulfur-containing polymers, wherein the uncured matrix A contains
a mercapto-terminated base polymer based on polyether, polythioether, polysulfide, copolymers thereof and/or mixtures thereof, wherein the mercapto-terminated polymer has a mercaptan content, based on the reactive SH groups to the total weight of the polymer, in the range of 0.8 to 8 wt %, and
a photoinitiator, which includes an α-aminoketone, that is activated on exposure to high-energy actinic radiation to form a tertiary amine compound as a catalyst after releasing an amine radical, which tertiary amine compound catalyzes a reaction between the mercapto-terminated base polymer and the isocyanate-based curing agent;
wherein the matrix A is free of (meth)acrylate-based compounds/polymers.

3. An uncured mixture B, which is a mixture of
an uncured matrix A based on sulfur-containing polymers, wherein the sulfur-containing polymers are mercapto-terminated base polymers based on polyether, polythioether, polysulfide, copolymers thereof, and/or mixtures thereof, wherein the mercapto-terminated polymer has a mercaptan content, based on the reactive SH groups to the total weight of the polymer, in the range of 0.8 to 8 wt %,
a curing agent containing isocyanate, the isocyanate having an average functionality in the range of 1.5 to 3.2, and
a photoinitiator, which includes an α-aminoketone, that is activated by exposure to high-energy actinic radiation and releases an amine radical, which forms an amine compound;
wherein the mixture B is free of (meth)acrylate-based compounds/polymers.

4. A sealant according to claim 1 , based on at least one mercapto-terminated polysulfide polymer.

5. An uncured matrix A based on sulfur-containing polymers for production of a sealant according to claim 2 , comprising at least one mercapto-terminated polysulfide polymer.

6. An uncured mixture B according to claim 3 , based on at least one mercapto-terminated polysulfide polymer.

7. A sealant according to claim 1 , wherein the sealant contains at least one additive selected from the group consisting of photosensitizers, fillers, lightweight fillers, thixotropy agents, plasticizers, adhesion promoters, antiaging agents, water scavengers, flame retardants, crosslinking agents and organic solvents.

8. An uncured matrix A based on sulfur-containing polymers for production of a sealant according to claim 2 , wherein the matrix A contains at least one additive selected from the group consisting of photosensitizers, fillers, lightweight fillers, thixotropy agents, plasticizers, adhesion promoters, antiaging agents, water scavengers, flame retardants, crosslinking agents and organic solvents.

9. An uncured mixture B according to claim 3 , wherein the matrix A and/or the mixture B contain(s) at least one additive selected from the group consisting of photosensitizers, fillers, lightweight fillers, thixotropy agents, plasticizers, adhesion promoters, antiaging agents, water scavengers, flame retardants, crosslinking agents and organic solvents.

10. A sealant according to claim 1 , wherein it contains a filler which is magnesium silicate hydrate, aluminum silicate, aluminum hydroxide and/or calcium silicate.

11. An uncured matrix A based on sulfur-containing polymers for production of a sealant according to claim 2 , wherein it contains as the filler magnesium silicate hydrate, aluminum silicate, aluminum hydroxide and/or calcium silicate.

12. An uncured mixture B according to claim 3 , wherein it contains as the filler magnesium silicate hydrate, aluminum silicate, aluminum hydroxide and/or calcium silicate.

13. A sealant according to claim 1 , having a Shore A hardness of at least 10, measured 5 to 600 minutes after initiating the high-energy actinic radiation, and a Shore A hardness in the range of 30 to 60, measured 2 weeks after initiating the high-energy actinic radiation.

14. A sealant according to claim 1 , having the following properties:
no cracks or other defects in the sealant, which occur during determination of a low temperature flexibility by bending at an angle of 30° at a temperature of 55±2°,
a tensile strength in the range of 0.5 to 2.8 MPa after 168 hours of storage in a fuel at a temperature of 60° C., after 300 hours of storage in a fuel at a temperature of 100° C. and/or after 1000 hours of storage in water at a temperature of 35° C.,
an elongation at break in the range of 100 to 800% after 168 hours of storage in fuel at a temperature of 60° C., after 300 hours of storage in fuel at a temperature of 100° C. and after 1000 hours of storage in water at a temperature of 35° C., and/or
a density in the range of 1.00 to 1.45 g/cm 3 .

15. A sealant according to claim 1 , having the following properties after complete curing:
a tensile strength in the range of 0.5 to 3 MPa,
an elongation at break in the range of 100 to 900% and/or
a peel resistance in the range of 50 to 300 N/25 mm.

16. A sealant as in claim 1 which is in contact with components contained in an aircraft.

17. A sealant as in claim 1 which is in contact with an aircraft, a space vehicle, an automobile, a rail vehicles, a ship, equipment, a machine, a building, furniture and an electronic device.

18. A sealant as in claim 1 which is in contact with a metallic substrate, a coated metallic substrate, a structural element, a sheet metal plate, carbon fiber reinforced plastic, or glass fiber reinforced plastic.

19. A sealant as in claim 1 which joins and/or bonds elements or seals and/or fills hollow spaces and/or interspaces of elements.

Assignees

• Chemetall Gmbh

Inventors

• Kralev Miroslav
• Sievers Björn
• Bons Peter
• Diez Francisco

Classifications

• C08L81/00

  Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing sulfur with or without nitrogen, oxygen or carbon only; Compositions of polysulfones; Compositions of derivatives of such polymers · CPC title

• B05D7/24

  for applying particular liquids or other fluent materials · CPC title

• C08L81/04

  Polysulfides · CPC title

• C09D181/00

  Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing sulfur, with or without nitrogen, oxygen, or carbon only; Coating compositions based on polysulfones; Coating compositions based on derivatives of such polymers · CPC title

• B05D3/06 Primary

  by exposure to radiation (B05D3/02 takes precedence {; plasma treatment B05D3/141}) · CPC title